Mixing Natural and Synthetic Surfactants: Co-Adsorption of Triterpenoid Saponins and Sodium Dodecyl Sulfate at the Air-Water Interface.

Saponins are highly surface active glycosides, derived from a wide range of plant species. Their ability to produce stable foams and emulsions has stimulated their applications in beverages, foods, and cosmetics. To explore a wider range of potential applications, their surface mixing properties with conventional surfactants have been investigated. The competitive adsorption of the triterpenoid saponin escin with an anionic surfactant sodium dodecyl sulfate, SDS, at the air-water interface has been studied by neutron reflectivity, NR, and surface tension. The NR measurements, at concentrations above the mixed critical micelle concentration, demonstrate the impact of the relative surface activities of the two components. The surface mixing is highly nonideal and can be described quantitatively by the pseudophase approximation with the inclusion of the quadratic and cubic terms in the excess free energy of mixing. Hence, the surface mixing is highly asymmetrical and reflects both the electrostatic and steric contributions to the intermolecular interactions. The relative importance of the steric contribution is reinforced by the observation that the micelle mixing is even more nonideal than the surface mixing. The mixing properties result in the surface adsorption being largely dominated by the SDS over the composition and concentration range explored. The results and their interpretation provide an important insight into the wider potential for mixing saponins with more conventional surfactants.

Nature of the Intermicellar Interactions in Ethoxylated Polysorbate Surfactants with High Degrees of Ethoxylation.

Ethoxylated polysorbate Tween nonionic surfactants are extensively used as foam and emulsion stabilizers and in aqueous solution form globular micelles. The ethoxylated polysorbate surfactants with higher degrees of ethoxylation than the Tween surfactants exhibit some interesting self-assembly properties. Small-angle neutron scattering, SANS, measurements have revealed intermicellar interactions which are more pronounced than the hard-sphere excluded volume interactions normally associated with nonionic surfactant micelles. The interactions are interpreted as arising from the partial charge on the ether oxygen of the ethylene oxide groups. This gives rise to an effective net negative charge on the micelles, which has been determined from the SANS data and zeta potential measurements. For degrees of ethoxylation of ⩽20, the effect is relatively small. The interaction increases with increasing ethoxylation such that for a degree of ethoxylation of 50 the interaction is comparable to that of ionic surfactant micelles. Unlike the intermicellar interaction in ionic surfactant micellar solutions, which results from the charge on the micelle arising from the partial binding of counterions, the interaction between ethoxthylated polysorbate surfactant micelles is unaffected by the addition of electrolyte.

[Differential diagnostic value of real-time tissue elastography and three dimensional ultrasound imaging in breast lumps].

OBJECTIVE: To investigate the real-time tissue elastography and 3D contrast-enhanced ultrasonography(CEUS) in breast lumps differential diagnostic value. METHODS: A total of 126 patients (180 lumps) with breast mass were retrospectively analyzed from December 2012 to December 2014 in Tumor Hospital Affiliated To Xinjiang Medical University.All patients were divided into three groups by using stratified random method.Each group was detected by real-time tissue elastography, 3D CEUS and two joint inspection.Each group of 42 cases (60 lumps) was confirmed by the pathological results as gold standard.Diagnostic sensitivity, specificity and coincidence rate of different methods were compared. RESULTS: The benign masses of ultrasound contrast showed the punctate, linear and nodular enhancement, and the border of enhancement was smooth.The malignant tumors were mainly dominated by uneven and high enhancement. There was no statistical difference in sensitivity, specificity and coincidence rate between elastography group and 3D CEUS group (64.7% vs 73.5%, 69.2% vs 76.9%, 66.7% vs 75.0%, all P>0.05). The sensitivity, specificity and coincidence rate of two joint inspection group were higher than those of elastography group and 3D CEUS group, the differences were statistically significant (97.1%, 92.3% and 98.3% , all P<0.05). CONCLUSION: 3D CEUS combined with real-time tissue elastography is of high value in the diagnosis of breast masses.

[Research advances of stem cell-based tissue engineering repair materials in promoting the healing of chronic refractory wounds on the body surface].

Repairing chronic refractory wounds on the body surface is a complex medical problem involving all stages of wound healing. In recent years, stem cells (SCs) and tissue engineering (TE) have brought hope for repairing chronic refractory wounds. SCs have excellent regenerative and paracrine effects; various TE strategies have the potential to repair chronic refractory wounds on the body surface and also improve the delivery efficiency of SCs. This article reviews the pathological characteristics of chronic refractory wounds, SCs used to repair chronic refractory wounds, and SC-based TE wound repair strategies.

Adsorption and self-assembly properties of the plant based biosurfactant, Glycyrrhizic acid.

There is an increased interest in the use of natural surfactant as replacements for synthetic surfactants due to their biosustainable and biocompatible properties. A category of natural surfactants which are attracting much current interest is the triterpenoid saponins; surface active components found extensively in a wide range of plant species. A wide range of different saponin structures exist, depending upon the plant species they are extracted from; but regardless of the variation in structural details they are all highly surface active glycosides. Greater exploitation and application requires a characterisation and understanding of their basic adsorption and self-assembly properties. HYPOTHESIS: Glycyrrhizic acid, extracted from Licorice root, is a monodesmosidic triterpenoid saponin. It is widely used in cosmetic and pharmaceutical applications due to its anti-inflammatory properties, and is an ingredient in foods as a sweetener additive. It has an additional attraction due to its gel forming properties at relatively low concentrations. Although it has attracted much recent attention, many of its basic surface active characteristics, adsorption and self-assembly, remain relatively unexplored. How the structure of the Glycyrrhizic acid saponin affects its surface active properties and the impact of gelation on these properties are important considerations, and to investigate these are the focus of the study. EXPERIMENTS: In this paper the adsorption properties at the air-water interface and the self-assembly in solution have been investigated using by neutron reflectivity and small angle neutron scattering; in non-gelling and gelling conditions. FINDINGS: The adsorption isotherm is determined in water and in the presence of gelling additives, and compared with the adsorption behaviour of other saponins. Gelation has minimal impact on the adsorption; apart from producing a rougher surface with a surface texture on a macroscopic length scale. Globular micelles are formed in aqueous solution with modest anisotropy, and are compared with the structure of other saponin micelles. The addition of gelling agents results in only minimal micelle growth, and the solutions remain isotropic under applied shear flow.

Surfactant/biosurfactant mixing: Adsorption of saponin/nonionic surfactant mixtures at the air-water interface.

Saponins are naturally occurring biosurfactants present in a wide range of plant species. They are highly surface active glycosides, and are used to stabilise foams and emulsions in foods, beverages and cosmetics. They have great potential for an even wider range of applications, especially when mixed with different synthetic surfactants. Understanding those mixing properties are key to the exploitation of saponins in that wider range of potential applications. The surface adsorption properties of the saponin, escin, with two conventional nonionic surfactants, polyethylene glycol surfactants, have been studied at the air-water interface using neutron reflectivity, NR, and surface tension, ST. Although the saponin and polyethylene glycol, CnEOm, surfactants are both nonionic the disparity in the relative surface activities and packing constraints result in non-ideal mixing. Comparison with the predictions of the pseudo phase approximation requires the inclusion of the quadratic, cubic and quartic terms in the expansion of the excess free energy of mixing to explain the variations in the surface composition. For escin/pentaethylene glycol monododecyl ether, C12EO5, the interaction is attractive and close to ideal. For escin/octaethylene glycol monododecyl ether, C12EO8, it is repulsive and close to the criteria for demixing. The differences in mixing behaviour are attributed to greater packing constraints imposed by the larger ethylene oxide headgroup of the C12EO8 compared to C12EO5.

Clonal integration supports the expansion from terrestrial to aquatic environments of the amphibious stoloniferous herb Alternanthera philoxeroides.

Effects of clonal integration on land plants have been extensively studied, but little is known about the role in amphibious plants that expand from terrestrial to aquatic conditions. We simulated expansion from terrestrial to aquatic habitats in the amphibious stoloniferous alien invasive alligator weed (Alternanthera philoxeroides) by growing basal ramets of clonal fragments in soils connected (allowing integration) or disconnected (preventing integration) to the apical ramets of the same fragments submerged in water to a depth of 0, 5, 10 or 15 cm. Clonal integration significantly increased growth and clonal reproduction of the apical ramets, but decreased both of these characteristics in basal ramets. Consequently, integration did not affect the performance of whole clonal fragments. We propose that alligator weed possesses a double-edged mechanism during population expansion: apical ramets in aquatic habitats can increase growth through connected basal parts in terrestrial habitats; however, once stolon connections with apical ramets are lost by external disturbance, the basal ramets in terrestrial habitats increase stolon and ramet production for rapid spreading. This may contribute greatly to the invasiveness of alligator weed and also make it very adaptable to habitats with heavy disturbance and/or highly heterogeneous resource supply.

The impact of electrolyte on the adsorption of the anionic surfactant methyl ester sulfonate at the air-solution interface: Surface multilayer formation.

The methyl ester sulfonates represent a promising group of anionic surfactants which have the potential for improved performance and biocompatibility in a range of applications. Their solution properties, in particular their tolerance to hard water, suggests that surface ordering may occur in the presence of multi-valent counterion. Understanding their adsorption properties in a range of different circumstances is key to the exploitation of their potential. Neutron reflectivity and surface tension have been used to characterise the adsorption at the air-aqueous solution interface of the anionic surfactant sodium tetradecanoic 2-sulfo 1-methyl ester, C14MES, in the absence of electrolyte and in the presence of mono, di, and tri-valent counterions, Na+, Ca2+, and Al3+. In particular the emphasis has been on exploring the tendency to form layered structures at the interface. In the absence of electrolyte and in the presence of NaCl and CaCl2 and AlCl3 at low concentrations monolayer adsorption is observed, and the addition of electrolyte results in enhanced adsorption. In the presence of NaCl and CaCl2 only monolayer adsorption is observed. However at higher AlCl3 concentrations surface multilayer formation is observed, in which the number of bilayers at the surface depends upon the surfactant and AlCl3 concentrations.

Biogenic amine ­ surfactant interactions at the air-water interface.

The strong interaction between polyamines and anionic surfactants results in pronounced adsorption at the air-water interface and can lead to the formation of layered surface structures. The transition from monolayer adsorption to more complex surface structures depends upon solution pH, and the structure and molecular weight of the polyamine. The effects of manipulating the polyamine molecular weight and structure on the adsorption of the anionic surfactant sodium dodecyl sulphate at the air-water interface are investigated using neutron reflectivity and surface tension, for the biogenic amines putrescine, spermidine and spermine. The results show how changing the number of amine groups and the spacing between the amine groups impacts upon the surface adsorption. At lower pH, 3-7, and for the higher molecular weight polyamines, spermidine and spermine, ordered multilayer structures are observed. For putrescine at all pH and for spermidine and spermine at high pH, monolayer adsorption with enhanced surfactant adsorption compared to the pure surfactant is observed. The data for the biogenic amines, when compared with similar data for the polyamines ethylenediamine, diethylenetriamine and triethylenetetramine, indicate that the spacing between amines groups is more optimal for the formation of ordered surface multilayer structures.

Differential chemosensitivity of breast cancer cells to ganciclovir treatment following adenovirus-mediated herpes simplex virus thymidine kinase gene transfer.

The development of resistance to radiation and chemotherapeutic agents that cause DNA damage is a major problem for the treatment of breast and other cancers. The p53 tumor suppressor gene plays a direct role in the signaling of cell cycle arrest and apoptosis in response to DNA damage, and p53 gene mutations have been correlated with increased resistance to DNA-damaging agents. Herpes simplex virus thymidine kinase (HSV-tk) gene transfer followed by ganciclovir (GCV) treatment is a novel tumor ablation strategy that has shown good success in a variety of experimental tumor models. However, GCV cytotoxicity is believed to be mediated by DNA damage-induced apoptosis, and the relationship between p53 gene status, p53-mediated apoptosis, and the sensitivity of human tumors to HSV-tk/GCV treatment has not been firmly established. To address this issue, we compared the therapeutic efficacy of adenovirus-mediated HSV-tk gene transfer and GCV treatment in two human breast cancer cell lines: MCF-7 cells, which express wild-type p53, and MDA-MB-468 cells, which express high levels of a mutant p53 (273 Arg-His). Treating MCF-7 cells with AdHSV-tk/GCV led to the predicted increase in endogenous p53 and p21WAF1/CIP1 protein levels, and apoptosis was observed in a significant proportion of the target cell population. However, treating MDA-MB-468 cells under the same conditions resulted in a much stronger apoptotic response in the absence of induction in p21WAF1/CIP1 protein levels. This latter result suggested that HSV-tk/GCV treatment can activate a strong p53-independent apoptotic response in tumor cells that lack functional p53. To confirm this observation, four additional human breast cancer cell lines expressing mutant p53 were examined. Although a significant degree of variability in GCV chemosensitivity was observed in these cell lines, all displayed a greater reduction in cell viability than MCF-7 or normal mammary cells treated under the same conditions. These results suggest that endogenous p53 status does not correlate with chemosensitivity to HSV-tk/GCV treatment. Furthermore, evidence for a p53-independent apoptotic response serves to extend the potential of this therapeutic strategy to tumors that express mutant p53 and that may have developed resistance to conventional genotoxic agents.

Heat-directed gene targeting of adenoviral vectors to tumor cells.

Targeting therapeutic gene expression to tumor cells represents a major challenge for cancer gene therapy. The strong transcriptional response exhibited by heat shock genes, along with the beneficial therapeutic effects of hyperthermia have led us to develop a heat-directed gene-targeting strategy for cancer treatment. Heat shock gene expression is mediated in large part by the interaction of heat shock factor 1 with specific binding sites (heat shock elements; HSE) found in the promoters of heat-inducible genes. Here we present a quantitative analysis of heat-inducible gene expression mediated by the wild-type hsp70b gene promoter, as well as a modified hsp70b promoter containing additional HSE sequences. Beta-galactosidase (beta-gal) expression was induced between 50- and 800-fold in a panel of human breast cancer cell lines infected with an adenoviral vector containing the wild-type hsp70b promoter (Ad.70b.betag) following treatment at 43 degrees C for 30 minutes. Infection with an adenoviral vector containing the modified hsp70b promoter (Ad.HSE.70b.betag) resulted in a 200- to 950-fold increase in beta-gal expression under the same conditions, and also provided a 1-2 degrees C decrease in the threshold of activation. Significant increases in the heat responsiveness of the Ad.HSE.70b.betag construct were observed in five of six tumor cell lines tested, as well as under thermotolerant conditions. Finally, we demonstrate that localized heating of a HeLa cell xenograft can effectively target beta-gal gene expression following intratumoral injection of Ad.70b.betag. Adenoviral vectors incorporating heat-inducible therapeutic genes may provide useful adjuncts for clinical hyperthermia.

Nodal nevi and cutaneous melanomas.

Nevocytes in melanoma-draining lymph nodes can be mistaken for melanoma metastases and may possibly transform to melanoma. During the development of a new technique for managing high-risk primary melanomas, selective lymph node dissection, we examined 4,821 nodes from 208 melanoma patients by light microscopy and immunohistochemistry. Nodal nevi were identified in 49 of 226 lymphadenectomy specimens (22%), a frequency considerably higher than previously recorded (5-6%). Nevi occurred in 57 of 4,821 nodes (1.2%), in 84% of patients in one node, in 13% of patients in two nodes, and in 3% of patients in three nodes. Nevocytes were detected in hematoxylin and eosin-stained sections in 38 of 49 cases (78%) and exclusively by immunocytochemistry with an antibody to S-100 protein in 11 of 49 (22%). Nevi were in the peripheral capsule in 93% of cases and in internal trabecula in the remaining 7%. Nevocytes surrounded a small vessel in 33% of cases. Nevi were more frequent in axillary (37 of 140, 26%) and cervical nodes (seven of 40, 18%) than in inguinal nodes (five of 46, 11%). Nevi were more frequent in sentinel nodes, the first nodes on the lymphatics draining a primary melanoma (11 of 284, 3.9%), than in nonsentinel nodes (46 of 4,537, 1.01%; p < 0.0008). One of 1,071 nodes from 50 patients with breast cancer (0.1%) and none of 521 nodes from 50 patients with pelvic cancer contained nevocytes. That nodal nevi are selectively present in melanoma patients raises the possibility of their origin from nodal melanocytes influenced by tumor products. Alternatively, the association may indicate that the nevocytes of cutaneous nevi can be disrupted and displaced by the growth of an adjacent melanoma.

Demonstration of cytoplasmic tyrosinase mRNA in tissue-cultured cells by reverse transcription (RT) in situ polymerase chain reaction (PCR) and RT PCR in situ hybridization.

To evaluate the specificity and applicability to the study of human tumor cells of the reverse transcription (RT) in situ PCR and RT polymerase chain reaction (PCR) in situ hybridization techniques, we examined five melanoma cell lines and five nonmelanoma lines for tyrosinase mRNA using primers specific for tyrosinase. Each procedural step was optimized and minutely controlled, and results from the in situ techniques and solution-phase RT-PCR were compared. All melanoma lines showed a specific pattern of perinuclear cytoplasmic reaction not seen in nonmelanoma lines. There was exact agreement between the results from the RT in situ PCR and RT-PCR in situ hybridization techniques and those from solution-phase RT-PCR. Ribonuclease digestion abolished cytoplasmic staining, as did omission of the reverse transcriptase step. Nuclear staining was seen in melanoma and nonmelanoma lines, apparently as a result of DNA synthesis from repair-replication and mispriming or nonspecific amplification. Neither high concentrations of deoxyribonuclease nor long incubation periods abolished this effect completely. Demonstration of cytoplasmic mRNA by RT in situ PCR and RT-PCR in situ hybridization specifically identifies cells of melanocytic lineage.

S-100 protein remains a practical marker for melanocytic and other tumours.

S-100 protein, extracted from bovine brain, is the first described of the modern generation of marker molecules for melanocytic tumours. Despite the observation that many different types of cells express S-100 protein, detection of the molecule in tumour cells in appropriate clinical and pathological circumstances is a widely used and effective adjunct to the determination that a tumour is melanocytic. Antibodies to S-100 protein are best deployed as part of a package that includes antibodies to other melanoma-associated epitopes (HMB-45, NKI-C3/Beteb), cytokeratins and common leukocyte antigen. Antibodies to S-100 protein may also increase the accuracy of melanoma staging and permit detection of small numbers of metastatic tumour cells that are not detectable by conventional histology. Future applications will probably include the wider use of antibodies to the S-100 protein monomers (alpha and beta) and the detection and quantification of S-100 protein in body fluids and tissues.

Antifibrin monoclonal antibodies for the detection of venous thrombosis.

In order to specifically detect the localization of thrombus in vivo, we have recently developed two monoclonal antibodies (SZ-58, SZ-63) which can specifically bind to cross-linked fibrin. The binding rates of the two monoclonal antibodies (MoAbs) to human plasma clots in vitro were 46.4 +/- 2.3% for 125I-SZ-58, 50.1 +/- 1.7% for 125I-SZ-63 and 3.4 +/- 1.6% for 125I-SZ-53 (control, MoAb against TM). It was shown that both SZ-58 and SZ-63 possess properties of inhibiting the polymerization of fibrin, and SZ-58 could also inhibit the aggregation of platelets induced by ADP. These characteristics make the two MoAbs suitable in the detection of thrombus in vivo. According to the cross reaction tests, thrombi in the jugular veins and carotid arteries in rabbits were made. After injection of the 125I-labeled MoAbs (100,000 cpm/ml of blood), the thrombi and the blood were taken and weighed at various time intervals and radioactivities were measured by an autogamma counter. The ratios of thrombus to blood radioactivity (T/B) of thrombi in jugular veins were 3.0, 5.6 and 3.0 for 125I-SZ-58, 1.5, 3.0 and 5.2 for 125I-SZ-63 and 1.2, 1.0 and 0.7 for control (125I-SZ-53) at the 3rd, 12th and 24th hour after the injection of the radiolabled MoAbs, while the radioactivities of arterial thrombi were almost the same as that in blood after the injection of the two radiotracers. Therefore, it can be concluded that both SZ-58 and SZ-63 can be used in venous thrombus imaging in vivo and the optimal times of imaging are at the 12th hour for SZ-58, 24th hour for SZ-63 after the injection of the radiolabled MoAbs.

[Histochemical localization of glyco-conjugate and CEA-glycoprotein in human lung neoplasms].

Sixty-six human lung neoplasms of different histological types and normal bronchial epithelial cells of newborn babies and adults were studied histochemically using ConA and PSA and the result was compared with that of CEA. Normal mucosal epithelium could bind to ConA, and the location of ConA receptors was related to the maturation of mucosal epithelial cells. Normal mucosal epithelium in adult bronchi failed to be stained with PSA and anti-CEA, and most of lung neoplasms could bind to PSA and positive for CEA, indicating that new glycoconjugate and CEA-glycoprotein could be synthesized after malignant transformation of mucosal epithelium. The binding of ConA, PSA and anti-CEA to cell membrane and nucleus membrane was characteristic of squamous cell lung cancer while lung adenocarcinoma mainly showed cytoplasmic staining. The weak staining of ConA, PSA and anti-CEA in small cell carcinoma and negative staining in carcinoid and malignant melanoma help testify that their origin may differ from that of squamous cell carcinoma and adenocarcinoma.

[Observation of platelet activation in coronary heart disease].

A monoclonal antibody specific for alpha-granule membrane protein (GMP-140) of platelets was used to evaluate the platelet activation degree in 16 cases with acute myocardial infarction (AMI) and 14 cases with unstable angina (UA). The number of GMP-140 molecules on platelet surface reached the highest 48 hours after AMI attack and returned to baseline at the seventh day. The concentration of GMP-140 in plasma began to increase at the first day and decreased to normal at the tenth day. The degree of platelet activation in patients with UA is less than that of AMI.

Interaction of a cationic gemini surfactant with DNA and with sodium poly(styrene sulphonate) at the air/water interface: a neutron reflectometry study.

The interactions between a dicationic gemini surfactant with a six-hydrocarbon spacer (1,2-bis(dodecyldimethyl-ammonio)hexane dibromide, C12C6C12Br2) and anionic polyelectrolyte DNA or sodium (polystyrene sulfonate) (NaPSS) at the air/solution interface have been studied and compared using neutron reflectometry together with surface tension. In the presence of the dichained cationic gemini surfactant, DNA and NaPSS display very different adsorption behaviors. The DNA/gemini mixtures show adsorption behavior very similar to that of DNA/C12TAB mixtures, with enhanced surfactant adsorption at low concentrations and thick structured layers at higher concentrations. However, for the NaPSS/gemini mixtures the amount of gemini at the surface is reduced relative to that in the absence of NaPSS at concentrations below the cmc. These differences in adsorption behavior are attributed to differences in the molecular structure and flexibility of the two polyanions. NaPSS is relatively hydrophobic and flexible enough to form bulk-phase polymer-micelle complexes with the gemini surfactant at low surfactant concentrations, whereas the adsorption of surface complexes is much less favorable because the dications on the gemini would require adjacent bulky pendant charges on the NaPSS to be oriented toward the surface. This would force the NaPSS to bend significantly whereas it is more favorable for the NaPSS to adopt an extended conformation at the surface. Thus, surfactant is actually removed from the surface to form bulk-phase complexes. In contrast with NaPSS, DNA has a far more rigid structure, and the charges on the backbone are at fixed intervals, factors that make the formation of surface DNA-monomer complexes much more favorable than bulk-phase DNA-micelle complexes. Finally, a short-chain sample of NaPSS consisting of only five to six segments adsorbs very strongly at the surface with the gemini to form more extensive layered structures than have previously been observed, consisting of approximately five sublayers.